Yanhong Chen¹ (chen7@uab.edu), Lingna Guo², Ri Jiang², Ke Zhou³, Xudong Zhao^2,4,5, Ming Meng¹; ¹The University of Alabama at Birmingham, Birmingham, USA, ²State Key Laboratory of Cognitive Science and Mental Health, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, ³Department of Psychology, Beijing Normal University, Beijing, China, ⁴CAS Center for Excellence in Brain Science and Intelligence Technology, Beijing, China, ⁵University of Chinese Academy of Sciences, Beijing, China

Can rodents form a categorical face concept, or is their ability to discriminate faces and objects driven solely by visual feature attributions? To answer this question, we trained sixteen C57BL/6J mice with a touchscreen face–object discrimination task and examined their behavior in two experiments. The image stimulus set comprises faces and control objects, which were matched on low-level visual properties. Mice entered unrewarded test sessions once they achieved >70% accuracy on two consecutive days in the training phase. In experiment 1, task accuracy across stimulus conditions was modeled with generalized linear mixed‑effects models (GLMMs). We found that, after training, mice exhibited above-chance performance on unencountered new face stimuli. Moreover, this performance decreased when stimuli were inverted or contrast‑negated, consistent with the classic effects of these manipulations on categorically “face‑specific” tasks in humans. In Experiment 2, sigmoid, linear, and quadratic functions were fitted to assess categorical face-recognition ability, the data were augmented using a simulation method. We found that along a continuum from low‑similarity pareidolia to real faces, mice’s performance followed a sigmoidal rather than a linear or quadratic function, which suggests a categorical face concept recognition boundary. Together, these results suggest that mice can form an abstract, configuration‑dependent face category and apply it in a human‑like manner. The work provides evidence that a face concept can emerge even in a species whose social communication is not primarily visual, paving the way for future investigations on neural and genetic substrates of categorical pattern recognition.